A billboard depicting Pope Francis with his thumb up located at Klokocina district in Nitra, Slovakia, Thursday, Feb. 5, 2015, invites voters to the Slovak national referendum on the protection of the traditional family scheduled for Saturday, Feb. 7. The Billboard slogans read (in clock-wise direction from left upper corner: "Come to referendum 7.2.2015", "Vote 3xYES" and " ´Slovakia fights brave today for the protection of the traditional family´ (as a quotation) - Pope Francis, Jan. 22, 2015, in Rome". The vote this weekend, which aims to reinforce the constitutional ban on same-sex marriages, and restrict the rights of gays to adopt children in this predominantly Roman Catholic nation follows a similar one that succeeded in Croatia in 2013 . Koller Jano, AP

Koller Jano, AP

A billboard depicting Pope Francis with his thumb up located at Klokocina district in Nitra, Slovakia, Thursday, Feb. 5, 2015, invites voters to the Slovak national referendum on the protection of the traditional family scheduled for Saturday, Feb. 7. The Billboard slogans read (in clock-wise direction from left upper corner: “Come to referendum 7.2.2015”, “Vote 3xYES” and ” ´Slovakia fights brave today for the protection of the traditional family´ (as a quotation) – Pope Francis, Jan. 22, 2015, in Rome”.

BRATISLAVA, Slovakia — A big billboard of Pope Francis hangs over the center of Slovakia’s capital, urging citizens to vote “Yes” in a referendum on restricting gay rights.

The vote this weekend in this predominantly Roman Catholic nation — which follows a similar one that succeeded in Croatia in 2013 — points to a cultural divide within the European Union in which more established western members are rapidly granting new rights to gays, while eastern newcomers entrench conservative attitudes toward LGBT people.

Last year, Britain became the latest EU nation to legalize gay marriage, joining nine others — all in the bloc’s west. Meanwhile, Croatia, Hungary, Poland and Slovakia in the EU’s east all have enacted constitutional bans on gay marriage.

In Saturday’s vote, Slovaks will be asked whether they agree to three points: that marriage can only be called a union between man and woman; that same-sex partners must be barred from adopting children; and that it’s up to parents to decide whether their children receive sex education.

While the constitution already defines marriage as between man and woman, the campaigners decided it was important to include the question in the referendum to reinforce traditional family values.

Slovakia’s anti-gay marriage movement has received massive support from the Catholic Church, and Francis this week even gave his blessing to the referendum in an address on St. Peter’s Square.

A conservative group, the Alliance for Family, forced the Slovakian vote by gathering more than 400,000 signatures, well above the required 350,000.

Anna Veresova, a leader of the alliance, called moves to redefine marriage and family in western Europe and the United States “nonsensical.”

She said it’s precisely because conservatives like her feel threatened by the West that the movement felt the need to act. “We can hardly say that Slovakia is an isolated island in the middle of an ocean that can’t be affected,” Veresova said. “That’s not true.”

Some 10,000 volunteers, from students to pensioners, have spread the alliance’s message across the country after major television networks – including the country’s public television network – refused to broadcast its campaign ad ridiculing the adoption of a child by a gay couple.